Automatic air-trap for pumps.



t PM 5. Gay??? Pm MM 0. S. AXFORD. AUTOMATIC AIR TRAP FOR PUMPS. APPLICATION FILED NOV. 29, 1906.

925,859. Pa'terited June 22, 1909.

I I HIIIH abbot/neg} CHARLES s. AXFORD, or rmmvinw, NEBRASLA.

AUTOMATIC AIR-TRAP FOR PUMPS.

Specification of Letters Patent.

Patented June 22, 1909.

Application filed November 29, 1905. Serial No. 289,695.

To all whom it may concern:

Be it known that 1, CHARLES S. Axronn, a citizen of the United States, residing at Plainview, in the county of Pierce and State of Nebraska, have invented certain new and useful Improvements in Automatic Air- Traps for Pumps, of which the following is a specification.

My invention relates to air traps for use in connection with pumps, and has for its object the provision of a device of this character which will prevent pumps from becoming air-bound.

Much annoyance has been experienced by engineers having charge of pumps, due to the fact that where said pumps receive their water supply at a comparatively low pressure, and discharge at a high pressure, the air entering with the water collects in the pump cylinder. It would seem at first glance that this would be driven out upon the discharge stroke of the piston, but such is not the ease. WVhen the pump is discharged against a high pressure, instead of being driven out of the cylinder against the high pressure, the air is merely compressed in the cylinder, then when the pump plunger makes its suction stroke, that compressed air expands and prevents the water from flowing into the pump cylinder, where it may be acted upon by the plunger. The result is that the pump instead of pumping water, compresses the air which has collected in the Water cylinder.

Further objects and advantages will be set forth in the detailed description which now follows.

The accompanying drawing illustrates a verticalsectional view of an air trap constructed in accordance udth the invention, showing said air trap applied to the valve chamber of a pump.

Referring to the drawing, the numeral 5 designates the water cylinder and the nu meral 6 the valve chamber, of an ordinary pump. Leading from the valve chamber of the cylinder, between the suction and discharge valves of the pump, is a short pipe 7, which is threaded at 8 into an air trap casing 9. Threaded at 10 into the casing 9 is a cap 11, having its central portion recessed as at 12, for the reception of the valve-disk 13. A web 14 having openings 15 formed therethrough, closes the bottom of recess 12, and provides a seat for valve-disk 13. Passing through web 14 is a pin 16, which is threaded at 17 into the top of a hollow lloat 18, which is disposed for vertical movement in casing 9. A pin 19, threaded at 20 into the bottom of said float, said pin being disposed for sliding movement in the channel 21 of a boss 22 formed upon the casing 9, provides means for guiding and holding the float in vertical alinement. A spring 23, which surrounds boss 22 and bears against the bottom of float 18, assists in raising the float, as will be hereinafter described.

Threaded at 2 1 into cap 11, is a check valve casing 25, the bottom of said casing being partially closed by a web 26 having an opening 27 a formed therethrough. lVeb 26 forms a seat for a check valve 27, which is normally held in engagement with said seat by a coil spring 28, said coil spring encircling a depending boss or stud 29 carried by cap 30, said cap being threaded at 31 into check valve casing 25. An exhaust pipe 32 provides means for permitting the escape of air through the trap when the pump is being started, as will be presently set forth.

The operation of the device is as follows: The herein described trap is connected to a pump intermediate the suction and discharge valves thereof, and at such a point that air confined within the pump cylinder, may flow through pipe 7 to the interior of easing 9. hen the pump is first started and until the water flows in and fills the pump cylinder, the air contained within the pump cylinder will be forced out through pipe 7, casing 9, openings 15, openings 33 which are formed in valve-disk 13, past check valve 27, and through exhaust pipe 82, to the atmosphere. This action will continue until the pump cylinder fills and water begins to flow through pipe 7. 'When a sufficient amount of water has entered casing 9, the buoyancy of float 18 assisted by spring 23, will lift said float and through pin 16, will force the valve-disk 13 against the web 26, thereby closing the opening 27 formed in said web to prevent either air or water from passing through the check valve to the exhaust pipe. The pump will then continue its operation in the usual manner, but if at any time suflicient air should collect in the pump cylinder to cause the water to leave float 18, said float will drop by gravity to the position illustrated in the figure of the drawing, thereby permitting the air which has collected in the pump cylinder, to be forced out through the check valve in the manner above described.

From the foregoing description, it will be seen that simple and eflicient means are herein provided for preventing the pumps becoming air-bound, thereby obviating a source of great annoyance and danger to engineers, for where pumps, which are used in boiler feed lines become air-bound, said pumps being started and stopped automatically by the height of Water in the boiler, it has often happened that the water reaches a dangerously low level before the fact that the pumphas become air-bound, is discovered.

l r hile the elements herein shown and described are well adapted to serve the purposes for which they are intended, it is to be understood that the invention. is not limited to the precise construction set fortlnbut that changes within the scope of the appended claim may be resorted to without departure from said invention.

Having thus described my invention, what I claim is:

In a device of the character described, the combination with a pump cylinder, of an air trap comprising a vertical cylindrical casing having connection with said cylinder between the suction and discharge valves thereof, and provided centrally of its base with an internal channeled boss, a cap plate threadedly engaging within the upper open end of said casing, having a central recess, and an outstanding internally threaded fiange surrounding said recess, said plate being provided with a central opening therethrough, and with apertures surrounding said opening and communicating between said recess thereof and the interior of the casing, a valve disk disposed within said recess, having apertures adjacent its edge, a closed cylindrical float disposed within said casing, having a pin projecting centrally from the lower end thereof and within the channel of said casing boss, and provided with a second pin, projecting centrally from the upper end thereof, and through the said cap wall opening, and secured centrally to the said valve disk within the said recess, a coil spring surrounding the said casing boss and bearing upwardly against said float, a cylindrical valve chamber having its lower end screwed within the said circular flange of said cap plate, and provided with a central opening in its lower end communicating with said cap plate recess, an imperforate valve disk mounted within said valve chamber, having a central boss, and seated upon the lower end of said chamber over the central opening thereof, an outlet port leading from said valve chamber above said valve disk, a cap plate threaded within the upper end of said chamber and provided with a central boss, and a coil spring surrounding, and extending between, the said valve disk boss, and the said cap plate boss, to force said valve disk upon its seat, substantially as described.

In testimony whereoi I aihX my signature in presence of two witnesses.

CHARLES S. AXFORD.

Witnesses Z. H. DE LANO, M. SORENSON. 

